Bloomin' marvellous

A satellite image of a massive phytoplankton bloom in the ocean around the Chatham Islands. Photo / Supplied, NASA

NASA has just released this amazing image of phytoplankton bloom around the Chatham Islands.

Taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite on December 5, it shows the massive annual spring-time bloom.

An array of colours from deep green to electric blue, NASA says the bloom is probably made up of many different types of marine life, mainly plant-like organisms called phytoplankton.

The highly productive waters support the blooms that sustatin valuable stocks of fish.

The phytoplankton contribute to making the ocean in this region a carbon sink - a place where the ocean takes in more carbon dioxide than it releases into the atmosphere.

According to NASA, the ocean is productive in this region because the topography of the ocean floor brings two currents together around the Chatham Islands.

The islands sit on the Chatham Rise, an underwater plateau that stretches from the South Island east to just beyond the Chatham Islands. The water north and south of the plateau is very deep.

Cold water from the Antarctic that is nutrient-rich but iron-poor flows south of the Chatham Rise. To the north is mostly warm water from the subtropics that is nutrient-poor but iron-rich.

The two pools of water come together in a current that rides over the plateau, mixing cold water with warm. The mixed water in the current provides both the nutrients and iron fertilisers needed to support large blooms around the Chatham Islands. The current, and therefore the bloom, is strongest in the spring and autumn.

- NZ Herald staff